用户头像从相机或者相册选择并剪裁

像微信、QQ、微博等社交类的APP，通常都有设置头像的功能，设置头像通常有两种方式：

1，让用户通过选择本地相册之类的图片库中已有的图像，裁剪后作为头像。

2，让用户启动手机的相机拍照，拍完照片后裁剪，然后作为头像。

我现在写一个简单的完整代码例子，说明如何在Android中实现上述两个头像设置功能。

MainActivity.java文件：

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package zhangpgil.photo;   import java.io.File; import android.support.v7.app.ActionBarActivity; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.Toast; import android.content.Intent; import android.graphics.Bitmap; import android.net.Uri; import android.os.Bundle; import android.os.Environment; import android.provider.MediaStore;   public class MainActivity  extends ActionBarActivity {        /* 头像文件 */      private static final String IMAGE_FILE_NAME = "temp_head_image.jpg";        /* 请求识别码 */      private static final int CODE_GALLERY_REQUEST = 0xa0;      private static final int CODE_CAMERA_REQUEST = 0xa1;      private static final int CODE_RESULT_REQUEST = 0xa2;        // 裁剪后图片的宽(X)和高(Y),480 X 480的正方形。      private static int output_X = 480;      private static int output_Y = 480;        private ImageView headImage = null;        @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);            headImage = (ImageView) findViewById(R.id.imageView);            Button buttonLocal = (Button) findViewById(R.id.buttonLocal);          buttonLocal.setOnClickListener(new View.OnClickListener() {                @Override              public void onClick(View v) {                  choseHeadImageFromGallery();              }          });            Button buttonCamera = (Button) findViewById(R.id.buttonCamera);          buttonCamera.setOnClickListener(new View.OnClickListener() {                @Override              public void onClick(View v) {                  choseHeadImageFromCameraCapture();              }          });      }        // 从本地相册选取图片作为头像      private void choseHeadImageFromGallery() {          Intent intentFromGallery = new Intent();          // 设置文件类型          intentFromGallery.setType("image/*");          intentFromGallery.setAction(Intent.ACTION_GET_CONTENT);          startActivityForResult(intentFromGallery, CODE_GALLERY_REQUEST);      }        // 启动手机相机拍摄照片作为头像      private void choseHeadImageFromCameraCapture() {          Intent intentFromCapture = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);            // 判断存储卡是否可用，存储照片文件          if (hasSdcard()) {              intentFromCapture.putExtra(MediaStore.EXTRA_OUTPUT, Uri                      .fromFile(new File(Environment                              .getExternalStorageDirectory(), IMAGE_FILE_NAME)));          }            startActivityForResult(intentFromCapture, CODE_CAMERA_REQUEST);      }        @Override      protected void onActivityResult(int requestCode, int resultCode,              Intent intent) {            // 用户没有进行有效的设置操作，返回          if (resultCode == RESULT_CANCELED) {              Toast.makeText(getApplication(), "取消", Toast.LENGTH_LONG).show();              return;          }            switch (requestCode) {          case CODE_GALLERY_REQUEST:              cropRawPhoto(intent.getData());              break;            case CODE_CAMERA_REQUEST:              if (hasSdcard()) {                  File tempFile = new File(                          Environment.getExternalStorageDirectory(),                          IMAGE_FILE_NAME);                  cropRawPhoto(Uri.fromFile(tempFile));              } else {                  Toast.makeText(getApplication(), "没有SDCard!", Toast.LENGTH_LONG)                          .show();              }                break;            case CODE_RESULT_REQUEST:              if (intent != null) {                  setImageToHeadView(intent);              }                break;          }            super.onActivityResult(requestCode, resultCode, intent);      }        /**       * 裁剪原始的图片       */      public void cropRawPhoto(Uri uri) {            Intent intent = new Intent("com.android.camera.action.CROP");          intent.setDataAndType(uri, "image/*");            // 设置裁剪          intent.putExtra("crop", "true");            // aspectX , aspectY :宽高的比例          intent.putExtra("aspectX", 1);          intent.putExtra("aspectY", 1);            // outputX , outputY : 裁剪图片宽高          intent.putExtra("outputX", output_X);          intent.putExtra("outputY", output_Y);          intent.putExtra("return-data", true);            startActivityForResult(intent, CODE_RESULT_REQUEST);      }        /**       * 提取保存裁剪之后的图片数据，并设置头像部分的View       */      private void setImageToHeadView(Intent intent) {          Bundle extras = intent.getExtras();          if (extras != null) {              Bitmap photo = extras.getParcelable("data");              headImage.setImageBitmap(photo);          }      }        /**       * 检查设备是否存在SDCard的工具方法       */      public static boolean hasSdcard() {          String state = Environment.getExternalStorageState();          if (state.equals(Environment.MEDIA_MOUNTED)) {              // 有存储的SDCard              return true ;          }  else {              return false ;          }      } }

布局文件有三个组件：放置头像的ImageView，两个Button，其中一个Button触发从本地相册选取图片作为头像的操作时间；另外一个Button触发手机拍摄照片作为头像的操作事件。activity_main.xml：

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<LinearLayout xmlns:android= "http://schemas.android.com/apk/res/android"      android:layout_width= "match_parent"      android:layout_height= "match_parent"      android:orientation= "vertical" >        <ImageView          android:id= "@+id/imageView"          android:layout_width= "wrap_content"          android:layout_height= "wrap_content"          android:src= "@drawable/ic_launcher" />        <Button          android:id= "@+id/buttonLocal"          android:layout_width= "wrap_content"          android:layout_height= "wrap_content"          android:text= "本地相册选取头像" />        <Button          android:id= "@+id/buttonCamera"          android:layout_width= "wrap_content"          android:layout_height= "wrap_content"          android:text= "手机拍照选取头像" />   </LinearLayout>